Formatting.
Remove CloneMapPanel and refactor.
Renamed 'instance' to 'mainInstance', since there is now more than one instance of Portal.data.LayerStore.
Removed unused class.
More refactoring, removal of unnecessary config.
Renamed mainInstance -> visualiseInstance.

Less ambiguous, more consistent with names of other components.
Merge pull request #675 from aodn/remove_clone_map_panel

Remove clone map panel